| 摘要 |
<p>A pressure pipe comprises recycled multi-layer pipe of at least 80 % polyethylene and at least 2 % polypropylene, the polyethylene and polypropylene being in separate layers of multi-layer pipe. The multi-layer pipe is granulated to granules of less than 20 mm maximum dimension. The granules are then melted and subjected to melt-phase mixing prior to extrusion to form the pressure pipe. The melt phase mixing is achieved by melting said granules in a pelletising extruder, chopping the extrudate therefrom into pellets of less than 10 mm maximum dimension; and supplying said pellets to an extruder for extruding said pipe. Alternatively the melt phase mixing is achieved by the granules being supplied to an extruder having intensive melt-phase mixing prior to an extrusion die for the pressure pipe.</p> |
